> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usefused.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Python imports

> Import authoring contracts from their Harnest domain.

Import each capability from its public domain module. The examples in this documentation use these paths so you can find related types and operations in one place:

```python theme={null}
from harnest.agent import Agent
from harnest.auth import AuthPrincipal, AuthenticationError
from harnest.lifecycle import lifecycle
from harnest.sandbox import Sandbox, control
from harnest.tool import tool, client_tool
```

## Domain imports

| Capability               | Public module                    | Examples                                                                            |
| ------------------------ | -------------------------------- | ----------------------------------------------------------------------------------- |
| Agents and graphs        | `harnest.agent`, `harnest.graph` | `Agent`, `Graph`, `Edge`                                                            |
| Authentication           | `harnest.auth`                   | `AuthPrincipal`, `Authenticator`, `AuthenticationError`, `principal_for`            |
| HTTP endpoints and hooks | `harnest.http`                   | `AgentInvoker`, `AgentResponse`, `HTTPCallRequest`, `HTTPLifecycleContext`          |
| Server configuration     | `harnest.server`                 | `ServerConfig`, `ServerLimits`, `load_server_config`                                |
| Tools                    | `harnest.tool`                   | `tool`, `client_tool`, `ClientToolError`, `ToolCallRequest`, `ToolLifecycleContext` |
| MCP                      | `harnest.mcp`                    | `MCPClient`, `MCPContext`, `MCPToolCallRequest`, `MCPToolCallError`                 |
| Models                   | `harnest.model`                  | `LiteLLMModel`, `LiteLLMContext`, `ModelCallRequest`, `ModelLifecycleError`         |
| Lifecycle                | `harnest.lifecycle`              | `lifecycle`, `Next`, `Finish`, `LifecycleCoverage`, `CoverageLevel`                 |
| Invocation context       | `harnest.context`                | `context`, `SessionContext`, `StorageContext`, `ScopedAssets`, `AgentSession`       |
| Sandbox providers        | `harnest.sandbox`                | `Sandbox`, `SandboxResult`, `SandboxCancelledError`, `control`                      |
| Runtime adapters         | `harnest.runtime`                | `ResponseRequest`, `InvocationRequest`, `RuntimeDriver`, `RuntimeEvent`             |
| Assets                   | `harnest.assets`                 | `AssetStorage`, `AssetScope`, `Stored`                                              |
| Storage                  | `harnest.store`                  | `MemoryStore`, `PostgresStore`, `RedisStore`, `CustomStorage`, `StorageRegistry`    |

Other existing domain modules include `harnest.approval`, `harnest.content`, `harnest.credentials`, `harnest.continuation`, `harnest.extensions`, `harnest.skills`, `harnest.task`, `harnest.logging`, and `harnest.tracing`.

`AgentResponse` from `harnest.http` represents an HTTP route response. `AgentResponse` from `harnest.context` represents a local agent invocation response; select the contract for your integration.

## Scoped operations

Sandbox execution and cleanup share a namespace:

```python theme={null}
from harnest.sandbox import control

with control.execute(timeout_seconds=30) as execution:
    execution.check()
    # Perform provider work with execution.remaining() as the I/O budget.

with control.cleanup(timeout_seconds=5) as cleanup:
    cleanup.check()
    # Release owned resources using cleanup.remaining() as the I/O budget.
```

`control.current()` returns the active scope. See [sandbox failure recovery and cleanup](/harnest/build/sandboxing#failure-recovery-and-cleanup) for cancellation and deadline guarantees.

Query lifecycle coverage with the same domain pattern:

```python theme={null}
from harnest.lifecycle import lifecycle

coverage = lifecycle.coverage("langgraph", "managed")
```